<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>成绩案例</title>
  <script src="../vue.js"></script>
  <style>
    .score-case {
      width: 1000px;
      margin: 50px auto;
      display: flex;
    }

    .score-case .table {
      flex: 4;
    }

    .score-case .table table {
      width: 100%;
      border-spacing: 0;
      border-top: 1px solid #ccc;
      border-left: 1px solid #ccc;
    }

    .score-case .table table th {
      background: #f5f5f5;
    }

    .score-case .table table tr:hover td {
      background: #f5f5f5;
    }

    .score-case .table table td,
    .score-case .table table th {
      border-bottom: 1px solid #ccc;
      border-right: 1px solid #ccc;
      text-align: center;
      padding: 10px;
    }

    .score-case .table table td.red,
    .score-case .table table th.red {
      color: red;
    }

    .score-case .table .none {
      height: 100px;
      line-height: 100px;
      color: #999;
    }

    .score-case .form {
      flex: 1;
      padding: 20px;
    }

    .score-case .form .form-item {
      display: flex;
      margin-bottom: 20px;
      align-items: center;
    }

    .score-case .form .form-item .label {
      width: 60px;
      text-align: right;
      font-size: 14px;
    }

    .score-case .form .form-item .input {
      flex: 1;
    }

    .score-case .form .form-item input,
    .score-case .form .form-item select {
      appearance: none;
      outline: none;
      border: 1px solid #ccc;
      width: 200px;
      height: 40px;
      box-sizing: border-box;
      padding: 10px;
      color: #666;
    }

    .score-case .form .form-item input::placeholder {
      color: #666;
    }

    .score-case .form .form-item .cancel,
    .score-case .form .form-item .submit {
      appearance: none;
      outline: none;
      border: 1px solid #ccc;
      border-radius: 4px;
      padding: 4px 10px;
      margin-right: 10px;
      font-size: 12px;
      background: #ccc;
    }

    .score-case .form .form-item .submit {
      border-color: #069;
      background: #069;
      color: #fff;
    }
  </style>
</head>

<body>
  <div id="app" class="score-case">
    <div class="table">
      <table>
        <!-- 表头 -->
        <thead>
          <tr>
            <th>编号</th>
            <th>科目</th>
            <th>成绩</th>
            <th>操作</th>
          </tr>
        </thead>

        <!-- 数据 -->
        <tbody v-if="list.length > 0">
          <tr v-for="(item,index) in list" :key="item.id">
            <td>{{index + 1}}</td>
            <td>{{item.subject}}</td>
            <td :class="{red : item.score<=60}">{{item.score}}</td>
            <td><a href="#" @click="del(item.id)">删除</a></td>
          </tr>
        </tbody>

        <!-- 暂无数据模块 -->
        <tbody v-else>
          <tr>
            <td colspan="5">
              <span class="none">暂无数据</span>
            </td>
          </tr>
        </tbody>

        <tfoot v-if="list.length > 0">
          <!-- <tfoot v-if="listFlag"> -->
          <tr>
            <td colspan="5">
              <span>总分：{{totalScore}}</span>
              <span style="margin-left: 50px">平均分：{{totalAvg}}</span>
            </td>
          </tr>
        </tfoot>
      </table>
    </div>

    <!-- 科目 -->
    <div class="form">
      <div class="form-item">
        <div class="label">科目：</div>
        <div class="input">
          <input v-model.trim="subject" type="text" placeholder="请输入科目" />
        </div>
      </div>

      <!-- 分数 -->
      <div class="form-item">
        <div class="label">分数：</div>
        <div class="input">
          <input v-model.number="score" type="text" placeholder="请输入分数" />
        </div>
      </div>

      <!-- 添加按钮 -->
      <div class="form-item">
        <div class="label"></div>
        <div class="input">
          <button @click="add" class="submit">添加</button>
        </div>
      </div>
    </div>
  </div>
  <script>
    const app = new Vue({
      el: '#app',
      data: {
        listFlag: true,
        list:
          JSON.parse(localStorage.getItem('list')) || []
        // [
        //   { id: 1, subject: '语文', score: 20 },
        //   { id: 7, subject: '数学', score: 99 },
        //   { id: 5, subject: '体育', score: 78 },
        //   { id: 12, subject: '英语', score: 70 },
        // ]
        ,
        subject: '',
        score: ''
      },
      methods: {
        del(id) {
          this.list = this.list.filter(item => item.id !== id)
          localStorage.setItem('list', JSON.stringify(this.list))
          if (this.list.length === 0) {
            this.listFlag = false
          }
        },
        add() {
          if (this.subject === '' || this.score === '') {
            alert('不能输入空内容')
            return
          }
          this.list.push({
            id: +new Date(),
            subject: this.subject,
            score: this.score
          })
          this.subject = ''
          this.score = ''
          localStorage.setItem('list', JSON.stringify(this.list))
        }
      },
      computed: {
        totalScore() {
          let total = this.list.reduce((prev, next) => prev + next.score, 0)
          return total.toFixed(2)
        },
        totalAvg() {
          let avg = this.totalScore / this.list.length
          return avg.toFixed(2)
        }
      }
    })
  </script>
</body>

</html>